These are just some random thoughts that have been going through my head today and I am curious to read other thoughts on the matter. I know a little about the human brain and how driven we are by hormones but not enough to hold a conversation with a Dr. in the field so forgive me if I express an assumption as fact.

I would like to hear who does or doesn't believe humans are meant to mate for life and why? I personally don't think we were, I think it is religious and societal pressure that makes us feel like we are supposed to marry, have kids, and buy cemetary plots next to each other.

I believe it is somewhere in the low, possibly 5% of mammals actually mate for life and even among those, mating for life is a term used losely. Basically they share responsibilities in raising offspring but they also "fool around".

A friend was explaining that we have a tendency to cheat because our brains eventually develop an immunity to the chemical reactions that cause the initial fireworks and we crave that feeling like a drug addiction. When those feelings are invoked by another, some resist but some can't seem to. In a lot of cases, a person's judgement becomes flawed, as if they were drunk, and make heat of the moment decisions that they would normally not think themselve capable. It makes sense that the fireworks would fade, so we can come back down and resume getting things done but what if we are not supposed to work to stay together for life?

By supposed to, I mean; what if our properties don't give us the necessity to stay together forever, rather, what if we are built for variety? Some people seem to fall in love and want to be together but just out of personal experience, after the first few years people seem to have to lower their expectations just to get through daily life with their partner.
What's your opinion?